 //设置cookie
  function setCookie(c_name,value,expiredays, domain){
    var exdate=new Date();
    exdate.setDate(exdate.getDate()+expiredays);
    document.cookie= c_name+ "=" +escape(value)+";path=/"+ ";domain="+domain+ ((expiredays==null) ? "" : ";expires="+exdate.toGMTString());
  }
  //获取cookie
  function getCookie(c_name){
    if (document.cookie.length>0)
    {
      c_start=document.cookie.indexOf(c_name + "=")
      if (c_start!=-1)
      {
        c_start=c_start + c_name.length+1
        c_end=document.cookie.indexOf(";",c_start)
        if (c_end==-1) c_end=document.cookie.length
          return unescape(document.cookie.substring(c_start,c_end))
      }
    }
    return ""
  }

  // 清除cookie
  function clearCookie(name, domain) {
    setCookie(name, " ", -1, domain);
  }

 